Below is a list of outside resources which can be very useful. This list will be continually updated as new resources are found.
RF Power Calculator
Every radio operator has the responsibility to operate safely. This includes knowing the maximum safe RF power levels for each setup. This calculator is a great resource for quickly estimating RF power levels in your radio shack, or any other location.
There's good grounding information on this site, as well as many other topics. Some things can be a bit difficult to read, but the underlying information is good.